(a) Field of the invention
The present invention relates to a pattern formation process for an integrated circuit substrate. Especially, the present invention relates to a pattern formation process that uses the metal spray method, the metal vapor deposition method or any combination thereof applying on the integrated circuit substrate to stuff the vias and PTHs ((Plated Through Holes) and to form the pattern including circuits and pads.
(b) Description of the Prior Art
As the electronic product getting smaller and lighter, the circuit board and the substrate manufacturer now are facing the strict requirement for multiple layers integrated circuit substrate. The circuit layout placed on the substrate is using the vias and the PTHs to connect and conduct each other. Basically, the PTH is fully penetrating through a substrate, while a via is not when several substrates added together. In general, the diameter of the via or the PTH is less than 100 μm and its line width is less than 50 μm. However, for the purpose of the density and the precision, the technology for manufacturing the micro via or the PTH with high density and high precision on the single or multiple layers integrated circuit substrate has been developed rapidly. And as the circuit board being wildly used, with higher depth/width ratio, manufacturing PTH with good electrical characteristic on a substrate with high precision is the major concern for many manufacturers.
Please refer to FIG. 1A to FIG. 1E, which showing the manufacture process to produce the via on an integrated circuit substrate in prior art, as shown, the process is including the steps as follows:
(a) providing a basic material as the main body of integrated circuit substrate 10, and on the top and the bottom side of the integrated circuit substrate 10, placing the top and bottom metal layers 11 and 12 used to define the circuit layout later;
(b) allocating the position of the PTHs on the predetermined position on the surface of the integrated circuit substrate 10, punching by the mechanical drilling to form a plurality of through holes 13 on the integrated circuit substrate 10;
(c) plating a complete plane with copper 14 in the inner side of the through holes 13 to form the electrical conducting PTHs (Plated Trough Hole) 13a; 
(d) proceeding Photolithograph, etching process on the circuit structure that being defined on the top and the bottom metal layer 11 and 12 on the top and the bottom surface of the integrated circuit substrate 10 to define the top and the bottom circuit layer 11a and 12a. 
(e) proceeding the filling process on the PTH 13a by filling up the PTH 13a with a resin material such as the solder mask to form the complete structure of conducting plug 14, and the last step is to place the protection layer on the surface of the top and the bottom circuit layer 11a and 12a of the integrated circuit substrate 10 for protection purpose.
The description above is the general manufacturing process for a single layer integrated circuit substrate. Basically, defining the PTHs in the aforesaid process for the single layer integrated circuit substrate and stacking the single layer integrated circuit substrates together will form the complex multiple layers integrated circuit substrate.
The process described above has been developed for many years in prior art, however, the disadvantages still exist; such as bad reliability, bad yield and so on. The major causes are as follows,
1. The solder mask is the most common used material in filling process fro the PTH 14, it is easy to form the gap space in the conducting plug 15 and to produce the popcorn, and further cause the difficulties of filling, the limitation of the diameter of the via, bad quality of electrical connection and bad reliability.
2. Making high quality via is a extremely complex process, the time for making such product is much longer, the manufacturing facility needed is expensive and the manufacturing cost is also high.
As the descriptions, the integrated circuit substrate that being made thru the conventional process is with the weakness such as bad reliability and bad intensity in the conducting plug, it always fails to meet the requirement from customer, also, the market competition is weak and the production cost is high. Therefore, the improvement of the process for producing via on the integrated circuit substrate is the major concern that every substrate manufacturer focused.